Went for a ride yesterday. Probably about 40 miles covered in about an hour with speeds varying between 30 & 50. Mostly twisties. My '01 2.7T behaved perfectly, and all gauges had normal readings. There were no warning lights. When we reached our destination, my wife opened the car before I switched off the engine. We both then heard a racket coming from under the hood. When I investigated, I found the sound was coming from a plastic or alloy wheel (about 6" diameter) that attaches to a shaft that comes out of the center of the top of the block and on which a single belt about 3/4" diameter travels off to the left. The sound to me sounded like a bad bearing, or something binding. It was a moderately loud; medium pitched rattle/grating sound that is definitely not part of the normal sounds of the engine.

I turned the car off, and restarted it about 15 minutes later. The sound was absent for about 45 seconds before beginning again. It was faint at first, and reached full volume in perhaps 10 seconds. We drove in town conditions a couple of miles, and stopped at a second location where the noise could again be heard before shutting off the engine. We dined, and perhaps 1 1/2 later drove the about 25 miles home. No problems or abnormalities on the trip. When I pulled into the garage, the noise was absent, and I haven't played with it yet today.

I have an appointment tomorrow AM at the dealer. We'll see if the noise reoccurs, and if any fault codes are stored. The service writer with whom I spoke yesterday seemed clueless.

This doesn't appear to be the infamous aux'l fan. I know that sound, and the temperatures are well below those that trigger it. Anyway, I can see the flimsy little thing behind the radiator and it isn't moving.

Anybody know enough about the 2.7T engine to tell me what the drive wheel I described is, what the belt does and where the shaft comes from? I know it can be difficult to isolate sounds in an engine compartment, but this is loud and troubling enough in nature to be clearly evident with the hood up. The sound also seems to be clearly emanating from this wheel distinct from any other area of the engine.

Anyone know what's going on? All thoughts and suggestions will be greatly appreciated.

 

AC, then turning the ECON button on and off to start and stop the compressor

 

I tend to agree w/2.7tdallas - see if it's A/C related. Most likely it's one of the accessories driven off that belt.

Hmmm, just looked at that .PDF of the 2.7T self-study guide and it says the pulley up top between the banks is the power steering pump drive pulley. Check your p/s fluid - that's one thing that's been seen to leak here before